Acetal polymers and use thereof in photosensitive compositions and lithographic printing plates

Abstract

This invention relates to a binder containing the units A, B, C, D and E, wherein A is present in an amount of 10 to 60 mole % and is of the formula ##STR1## B is present in an amount of 1 to 30 mole % and is of the formula ##STR2## C is present in an amount of 5 to 60 mole % and is of the formula ##STR3## D is present in an amount of 0 to 60 mole % and is of the formula ##STR4## E is present in an amount of 1 to 40 mole % and is of the formula ##STR5## wherein X is an aliphatic, aromatic or araliphatic spacer group, R 1 is hydrogen or an aliphatic, aromatic or araliphatic group, R 2 , R 3 and R 4 are hydrogen or alkyl groups with carbon numbers of from 1 to 18 and Y is a saturated or unsaturated chain- or ring-shaped spacer group, and photosensitive compositions containing this binder.

We claim: 
     
       1. A photosensitive composition comprising: (i) a diazonium polycondensation product or a free radical polymerizable system consisting of photoinitiators and free radical polymerizable components or a hybrid system consisting of a diazonium polycondensation product and a free radical polymerizable system consisting of photoinitiators and free radical polymerizable components, and   (ii) a binder containing the units A, B, C, D and E, wherein A is present in an amount of 10 to 60 mole % and is of the formula ##STR13## B is present in an amount of 1 to 30 mole % and is of the formula ##STR14## C is present in an amount of 5 to 60 mole % and is of the formula ##STR15## D is present in an amount of 0 to 60 mole % and is of the formula ##STR16## E is present in an amount of 1 to 40 mole % and is of the formula ##STR17## wherein X is an aliphatic, aromatic or araliphatic spacer group, R 1  is hydrogen or an aliphatic, aromatic or araliphatic group, R 2 , R 3  and R 4  are hydrogen or alkyl groups with carbon numbers of from 1 to 18 and Y is a saturated or unsaturated chain- or ring-shaped spacer group.     
     
     
       2. The composition of claim 1 containing a polycondensation product from 3-methoxy-diphenylamine-4-diazonium sulfate and 4,4'-bis-methoxymethyldiphenyl ether precipitated from an aqueous solution as organic sulfonate, tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate or hexafluoroarsenate as the photosensitive component. 
     
     
       3. The composition of claim 1 containing a free-radical forming photoinitiator or mixtures of photoinitiators and coinitiators rendering the composition sensitive to the wavelengths from 300 to 800 nm as well as free radical polymerizable components with unsaturated groups as the photosensitive component. 
     
     
       4. The composition of claim 1 further comprising an exposure indicator, a dye or pigment for increasing the contrast of the image as well as an acid for stabilizing the photosensitive composition.